1. Field of the Invention
This invention relates to powders suitable for manufacturing electrodes adapted for producing hydrogen by electrolysis such as in water electrolyzers, chlorate and also capable of being used in chlor-alkali or the like cells. More particularly, the invention is concerned with the manufacture of nanocrystalline powders of alloys of nickel, molybdenum and oxygen by high energy mechanical deformations, said powders having a high electrocatalytic activity for hydrogen evolution when used in water electrolyzers, chlor-alkali, chlorate and the like cells.
2. Description of Prior Art
It is known that a successful electrolysis of alkaline water can be achieved using an electrode consisting of an alloy of an element selected from the group consisting of nickel, cobalt, iron and one from Mo, W, V. Such an electrode is normally made of an alloy of nickel and molybdenum, wherein nickel is used in predominant amount.
U.S. Pat. No. 4,358,475 issued on Nov. 9, 1982 to the British Petroleum Company Limited discloses a method of producing metal electrodes by coating a substrate with a homogeneous solution of compounds of iron, cobalt or nickel and compounds of molybdenum, tungsten or vanadium. The coated substrate is thereafter thermally decomposed to give an oxide-coated substrate which is then cured in a reducing atmosphere at elevated temperature. This method produces good electrodes but is obviously complicated, expensive to achieve and time consuming. The same technology is also disclosed in the following publications:
Int. J. Hydrogen Energy, Vol. 7, No. 5, pp. 405-410, 1987, D. E. Brown et al.
Electrochimica Acta, Vol. 29, No. 11, pp. 1551-1556, 1984, D. E. Brown et al.
On the other hand, alloys of nickel and titanium and of nickel and niobium in the form of amorphous powders have been produced by mechanical alloying in a laboratory ball/mill mixer, as disclosed in:
Appl. Phys. Lett. 49(3), 21 July 1986, pp. 146-148, Ricardo B. Schwarz et al.
E. Hellstern et al., at a Symposium on "Multicomponent Ultrafine Microstructures" held in Boston, Mass. on Nov. 30, 1988, discloses the preparation of nanocrystalline AlRu by ball milling. The process is essentially restricted to Ru and AlRu and there is no disclosure of the usefulness of the product obtained thereby.
D. E. Brown et al, in The Development of Low Overvoltage Cathodes, Electrode Coatings, pp. 233-245 disclose the suitability of nickel-molybdenum alloy coated electrodes in chlor-alkali cells.
Finally, A. W. Weeber et al. review the production of amorphous alloys by ball milling in: Physica B, Vol. 153, pp. 93-135, 1988, A. W. Weeber and H. Bakker.
The prior art is therefore completely devoided of any disclosure of electrodes which have been manufactured by mechanical alloying.
It is an object of the present invention to provide powders which can be used with advantage to produce electrodes that may be utilized in the electrolytic production of hydrogen.
It is another object of the present invention to provide powders having a unique morphology and microstructure, which differ from those produced by other techniques and which can be used with advantage to manufacture hydrogen producing electrodes.
It is another object of the present invention to manufacture low cost cathodes which can be used to produce hydrogen by means of a simple technique of fabrication without requiring chemical, thermal or electrochemical treatment of the materials.
It is another object of the present invention to provide an electroactive powder for the manufacture of electrodes without requiring a substrate during fabrication.
It is another object of the present invention to provide agglomerated nanocrystals of an alloy which may be used as a cathode for the production of chlorates.
It is another object of the present invention to produce chlorates by carrying the electrolysis in an electrolytic cell having a cathode comprising the above powders.